The Illusion Fog Barrier (無限結界 Mugen Kekkai ) is a powerful barrier that seals off the entrance to the Wailing Demon Territory, preventing Kyouma from entering the continent. The Barrier is activated in the altar of a temple nearby.
The temple is protected by twenty pillars of Salt, preventing Kyouma from approaching it. When activated, it shrouds the area inside it in Fog. With the power of the Saint of Illusions, the barrier makes anyone straying near the border turn back, keeping them from entering or leaving.
Rowen taught the Braves that to activate the barrier one had to insert the sword into the pedestal in the altar, place their hand on the slate and then recite the line: "Fog, come forth". However, it is later revealed by Hans that the true way to activate the barrier is to remove the sword, spread blood and then break the slab while reciting: "I am the owner of the barrier".